text: const userInput = document.querySelector("#input-number");
  const addBtn = document.querySelector("#btn-add");
  const subtractBtn = document.querySelector("#btn-subtract");
  const multiplyBtn = document.querySelector("#btn-multiply");
  const divideBtn = document.querySelector("#btn-divide");
  const currentResult = document.querySelector("#current-result");
  
  let defaultResult = 0;
  
  const output = (result) => {
      currentResult.textContent = result;
  }
  
  const add = _ => {
      const enteredNumber = parseInt(userInput.value);
      defaultResult += enteredNumber;
      console.log(defaultResult);
      output(defaultResult);
  }
  
  const subtract = _ => {
      const enteredNumber = parseInt(userInput.value);
      defaultResult -= enteredNumber;
      output(defaultResult);
  }
  
  const multiply = _ => {
      const enteredNumber = parseInt(userInput.value);
      defaultResult *= enteredNumber;
      output(defaultResult);
  }
  
  const divide = _ => {
      const enteredNumber = parseInt(userInput.value);
      defaultResult /= enteredNumber;
      output(defaultResult);
  }
  
  addBtn.addEventListener("click", add);
  subtractBtn.addEventListener("click", subtract);
  multiplyBtn.addEventListener("click", multiply);
  divideBtn.addEventListener("click", divide);